There are many cases, particularly in communication and computer circuits, where a large number of conductors from one source of supply is to be connected to another array of conductors leading to other or output circuits. There are many times when such connections may be changed and reconnected to fit another pattern. This is often the case in the telephone circuits where the receiver set must be reconnected in conformity with new receiver locations. A convenient means of changing the contact array is the matrix or cross bar switch described herein. One series of conductors is connected to one set of parallel cross bars, the other series of conductors being connected to the other set of cross bars positioned at right angles to the first set. When no connecting pins are used there is no connection between any of the conductor sets. Any one of the conductors in one set can be joined to any one of the conductors in the other set by inserting a connecting pin in the proper hole. If desired one conductor from one set may be connected to all the conductors in the other set by inserting connecting pins in all the holes in one line in the cover plate. Change of connections is made by merely relocating a connecting pin.
The size of a given matrix board is determined by the spacing between contacts. The industry's trend towards miniaturization makes it necessary to reduce the contact spacing to a minimum consistent with reliable operation. The latter requirement implies the need for very accurate alignment between the corresponding contacts of the upper and lower layers respectively, so that the contact pins, when inserted, provide a low resistance electrical path. Furthermore, each contact must exert a reproducible and consistent contact peressure on the contact pin, regardless of how many pins are inserted in a given row of contacts.
Existing matrix boards having contact spacings of less than 1/4 inch do not meet the above criteria in one or more respects. Their design does not insure accurate alignment and/or the contact pressure is dependent upon the number of pins inserted in a row.
Accordingly, it is an object of the present invention to provide a miniaturized, matrix programming board to overcome the shortcomings of the prior art, and achieve, by its features, the desired end result.
A further feature of the present invention is a pair of cover plates which protect the cross bars and which form a mechanical guide means for the contacting pins, as well as electrically separating said cross bars.
Another feature of the invention is the cylindrical, split, contact socket positioned under each contact position for forming a dependable electrical contact between the cross bar and the contacting pin.
Still another feature of the invention is the ability to insert a semiconductor diode between the connected cross bars to restrict the passage of current to one direction.